Manufacture of viscose rayon



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United States Patent Ofifice 3,026,169 Patented Mar. 20, 1962 3,026,169MANUFACTURE OF VISCOSE RAYON Brewster B. Eskridge, Candler, N.C.,assignor to American Enka Corporation, Enka, N.C., a corporation ofDelaware No Drawing. Filed Mar. 23, 1960, Ser. No. 16,938 8 Claims. (Cl.18-54) This invention relates generally to the production ofshapedarticles of regenerated cellulose from viscose and more particularly tothe production of high tenacity viscose rayon yarn. In recent years,extensive research has been conducte by all rayon producers in an effortto improve the prod- A most effective modifier is disclosed in copendingapplication Serial No..609,792, filed September 14, 1956, and owned bythe common assignee. This modifier is a quaternary derivative of anethoxylated amine. Compounds of this type have the following generalformula:

tonmnonn R-N R/ wcnHznohwherein R is an alkyl, aryl, or alicyclicradical of at least six carbon atoms, and usually not more than twenty;R is an alkyl radical containing one to three carbon atoms; Z representsan anion having substantially no surface activity such as hydroxide,halide, sulfate, acetate, etc.; .1: and y are whole numbers; X plus y is2 to 50; and n is also a whole number of one to three. These compoundsare known in the trade as Ethoquads. For further description and themethod of preparation of these compounds, reference should be had to theaboveidentified copending application.

In the use of the Ethoquads and other modifiers, the improved strengthsthat have been obtained have been at the expense of ease inmanufacturing. The modified yarns are tender until completelyregenerated; therefore, the spinbath acid concentration must becontrolled to insure good spinnability, satisfactory yarn quality, andhigh strength. In most cases, the range of spinbath acid concentrationwhich achieves these results is very narrow and usually just above theminimum acid concentra tion necessary to maintain satisfactoryspinnability. With the constant changing of the acid spinbath, it can beseen that it is very difficult to maintain the spinbath acid within therequired narrow range. If the acid is outside of this range, there willbe a reduction in satisfactory spinnability and, in some cases, theviscose solution may not evenbe spinnable. In addition, there will be areduction in quality and strength. Ali o-f these are obviouslyundesirable, out previously were thought to be characteristic ofmodified spinning.

It is therefore an object of this invention to provide a viscosespinning solution which may satisfactorily be spun over a wider range ofacid concentrations.

It is a further object of this invention to provide a modified viscosespinning solution having incorporated therein an additive which permitsimproved spinning over a wider range of acid concentrations.

An additional object of this invention is to provide a process formaking viscose rayon yarn that is free of the difficulties of the priorart.

A further object of this invention is to provide a process formanufacturing viscose rayon yarn wherein the spinbath acid concentrationis not as critical as in the processes of the prior art.

An additional object of this invention is to provide a new and improvedadditive for the viscose process which enables satisfactory spinningover a wider range of spinbath acid concentrations.

These and other objects will become apparent to one skilled in the artfrom a reading of the following detaileddescription of this inventionThe above objects of this invention are accomplished by incorporatinginto a viscose spinning solution a sodium lignosulfonate and aquaternary derivative of an ether;- ylated amine. The thus improvedviscose spinning solution is extruded through a spinneret into a zinccontaining acid coagulating bath to form filamentary material therefrom.They are then preferably passed into a second bath containing a hotsulfuric acid where they are stretched. The regeneration of the yarn isthus completed while the filaments are under tension. Thereafter theyarn is collected in package form.

- The above identified quaternary derivative of an ethoxylated aminethat is incorporated into the viscose spinning solution is described inapplication Serial No. 609,792.

These compounds, known in the trade as Ethoquads, are obtained byquaternizing with suitable alkyl compounds alkali-soluble ethyleneoxideadducts of primary fatty amines. These adducts and their method ofpreparation are described in US. Patent No. 2,852,334, and are known inthe trade as Ethomeens.

Examples of these viscose modifiers are obtained by the followingreactions:

0 H; C 11 0MB:

Ethomeen 0/12 on, onzonzm n I Ethoquad 0/12 R derived from coconut oil 2plus y=2 (2) )CHzCHzOhH (CHzCHzOhH R-N 011301 R7N\ o1 CHQC 2OM a (c zzmy Ethomeen 0/20 Ethoquad 0/20 R derived from coconut oil :2: plus y=10(3i /(CHGH O),H }CH2CH2O)XH RN CHaCl R;N Ol- CHz CHaObH CH; iCH cHzm HEthomeen (3/25 Ethoquad (3/25 E derived from coeonutrfatty acids I plusy=15 (6) (CH2CH20).:H R-N CHaCl Hz C H2 0 yH Ethomeen T/60 C (CH2CH20) HEthoquad T/20 R derived from tallow :r plus 11:10

The sodium lignosulfonates are obtained by the sulfonation of alkalilignin. These compounds are known in the trade as Polyfons. It ispossible to use these compounds with a variety of degrees ofsulfonation. For example, those compounds with one-half, one, two,three, or four moles of sulfonation per lignin unit of 840 grams, may beused in this invention. These compounds are known as Polyfon H, O, T, R,and F, respectively.

In order to accomplish the objects of this invention, these compoundsare preferably injected into the viscose spinning solution just priortospinning. However, they may also be added at any point in thepreparation of the spinning solution. The quaternary derivatives of anethyloxylated amine may be added inv amountsof about 0.5% to 4.0%, basedon oven dry, recoverable cellulose: in the viscose spinning solution(hereinafter referred to as (CIV).

The sodium lignosulfonates are preferably incorporated in amounts ofabout 0.5% to- 3.0% (CIV) into. the viscose spinning solution". Largeror smaller amounts of either compound may be used without materiallyaffecting the physical properties of the resulting yarn.

Beneficial results may be obtained by using a viscose spinning solutioncontaining 4 to 8% cellulose, 4 to 8% total alkali content expressed asNaOH, and 1.210 3.25% total sulfur content. Higher or lowerconcentrations may be used if desired without materially affecting theresults. The viscose spinning solution may have an ammonium chloridenumber of 10 to 21 and a spinning viscosity of 30 to 100. Higher orlower maturities and viscosities may also be used without appreciablyaffecting the results of this invention. The above concentrations arebased on the weight of the viscose spinning solution.

The freshly extruded filaments are permitted to travel through the acidor coagulating-regenerating bath for a distance of 8 to 200 inches;however, an immersion of 10 to-60 inches is preferred. The acidcoagulating bath should preferably contain sulfuric acid, sodiumsulfate, and zinc sulfate. Other materials, such as magnesium sulfate,may be added for special purposes, if desired. The sulfuric acid contentmay vary from about 2.5 to 7.0%, the sodium sulfate from about 5.0 to20.0%, and; the zinc sulfate from about 3.0 to 15.0%. It should beunderstood that these are preferred ranges and that higher or lowerconcentrations, which concentrations are based on the weight of thecoagulating bath, may be used without departing from this invention. Thetemperature of this bath generally Will range from about 30 to 70 C.,and the preferred temperature is about 50 C.

The speed at which the filaments may be spun should preferably not be inexcess of 90 meters per minute because of possible filament damage.However, the speed should not be so low as to render the processuneconomical. Usually a speed of from 35 to 65 meters per minute willeconomically produce an excellent yarn. With the higher speeds, it. isusually desirable to use a spinning tube immersed in the acidcoagulating bath. Such a tube is described in U.S. Patent No. 2,908,937.

The treatment of the yarn following the second bath is conventional andforms no part of this invention. It normally consists of a. washing stepor steps, a desulfurizing step, a finishing step, and a drying step. Ifthe The second or regenerating bath may be water, 1 to Q 6% sulfuricacid, or substantially diluted acid coagulating bath. It may alsocontain 1 to 6% sulfuric acid, 0.0 to 1.5% zinc sulfate, and 0.0 to 3.0%sodium sulfate. A preferred composition for this bath is about 4.0%,sulfuric acid, 1.2% sodium sulfate, and 0.3% zinc sulfate.

'The temperature of this bath may vary from 50 to 100 C., with thepreferred temperature being from 85 to 100. C. Stretch preferably isimparted to the filaments while they are immersed in the second bath.This stretch may vary from 20 to 150% and preferably is from 100 to110%,

yarn is, to be used for-textile purposes, it may include a bleachingstep.

This invention will be, more clearly understood by ref erence to theexamples and discussions which follow. These examples are given merelyfor purposes of illustration and are not to be construed as limiting thescope of this invention.

EXAMPLE I Several viscose spinning solutions containing 7.5% cellulose,5.5% total alkali expressed as NaOH, 2.3% total sulfur, and 2.5% (CIV)of Ethoquad C/25 were prepared in a conventionaLmanner. The solutionshad maturities of 16 to 18 ammonium chloridenumbers and viscosities 'of'40 to .50 seconds at 20 C. The-viscoses were spun into an 1100denier-+720 filament yarn, after drawing, by extrusion through. aspinneret. with. 60 microns. diameter holes into several acidcoagulating baths. The sulfuric acid concentration of these baths werevaried as shown in the following Table 1. Each bath contained 9.0%sodium sulfate and 9.0% zinc sulfate. The bath temperatures were 50 C.,and the total yarn travel therein was between 20 and 30 inches. Fromthese baths the yarns were led to first feed wheels, thence to secondacid baths at 92 C., and the yarn travel therein was 40 inches. Thesesecond acid or regenerating baths contained 4.0% sulfuric acid, 1.2%sodium sulfate, and 0.3% zinc sulfate. The yarns were then led to secondfeed wheelsrotating at peripheral speeds of 40 meters per minute andthence to bobbins: or spools. The differences in peripheral speeds. ofthe 'first and second feed wheels were such as to impart to stretch tothe yarns in the second baths and to create tension on the yarnsimmediately before the-second feedwheels. The peripheral speeds of thebobbins or spools. were such as to maintain. the same tension on theyarns as they were collected. "The yarns were aftertreated in theconventional manner. Two strands of each yarn were plied together ina.conventional manner to form: 15 ,x 15 cords. The following tableillustrates the oven dry strengths and 'deniers of the samples. for eachsulfuric acid concentration of. the acid coagulating bath.

EXAMPLE n Viscose spinning solutions of compositions similar to thosedescribed in Example I were prepared, except that 2.5% (CIV) of PolyfonO was injected into the solution. The viscoses were spun and treated asin Example I, except the sulfuric acid concentrations of the acid,coagulating bath were as shown in Table II. This Table II illustratesthe strength and denier of '15 x 15 cords formed from the yarns at thevarious acid concentrations.

EXAMPLE III Viscose spinning solutions of compositions similar to thosedescribed in Example I were prepared, except 2.5% (CIV) of Polyfon T wasinjected into the solution. The viscoses were spun and treated as inExample 1, except the sulfuric acid concentrations of the acidcoagulating bath were as shown in Table III. This Table III illustratesthe strength and denier of x 15 cords formed from the yarns at thevarious acid concentrations.

Table III Oven Sulfuric Acid (percent) Dry Denier Strength EXAMPLE IVViscose spinning solutions of compositions similar to those described inExample I were prepared, except 2.5

(CIV) of Polyfon F was injected into the solution. The viscoses werespun and treated as in Example I, except the sulfuric acidconcentrations of the acid coagulating bath were as shown in Table IV.This Table IV illustrates the strength and denier of 15 x 15 cordsformed from the yarns at the various acid concentrations.

Table IV Oven Sulfuric Acid (percent) Dry Denier Strength From theforegoing examples, it can be seen that the compounds of this invention,when used in a viscose process, not only produce high strength butrender the acid concentration of the acid coagulating bath lesscritical. This permits greater freedom in spinning and permits greaterfluctuation in acid concentrations, thereby simplifying the control ofthe spinning operation. In addition, it permits spinning at lower acidconcentrations, thereby reducing the cost of the operation. It can alsobe seen from these examples that yarn of desirable properties may beobtained at acid concentrations which are not just above the acidconcentrations at which the modified viscose will not spin. This alsosimplifies the control of the spinning operation.

Many modifications may be made in this invention without departing fromits spirit and scope. For instance, formaldehyde may be added to theacid coagulating bath, or it may even be used in an intermediate bath.It should be understood that this invention is to be limited only by thefollowing claims.

What is claimed is:

1. A viscose spinning solution having incorporated therein about 0.5% to4.0% CIV of a compound of the general formula:

wherein R represents an alkyl, aryl, or alicyclic radical containing atleast six carbon atoms, R is an alkyl radical containing one to threecarbon atoms, x plus y is two to fifty, x and y are whole numbers, n isa whole numher from one to three, and Z is a surface inactive anion, anda sodium lignosulfonate having about 0.5 to 4.0 moles of sulfonation permole of lignin.

2. A viscose spinning solution according to claim 1 wherein about 0.5%to 3.0% CIV of the sodium lignosulfonate is incorporated into theviscose spinning solution.

3. A viscose spinning solution according to claim 1 wherein saidlignosulfonate has one mole of sulfonation per mole of lignin.

4. A viscose spinning solution according to claim 1 wherein saidlignosulfonate has two moles of sulfonation per mole of lignin.

5. A viscose spinning solution according to claim 1 wherein saidlignosulfonate has four moles of sulfonation per mole of lignin.

6. A viscose spinning solution according to claim 1 wherein thequaternary derivative of an ethoxylated amine has the following formula:

C a z zmy in which R represents an aliphatic radical containing six totwenty carbon atoms, x and y are whole members, and x plus y is two tofifty.

7. A process of producing viscose yarn which comprises spinning aviscose solution, having incorporated therein about 0.5 to 4.0% CIV of acompound of the general formula:

wherein R represents an alkyl, aryl, or alicyclic radical containing atleast six carbon atoms, R is an alkyl radical containing one to threecarbon atoms, x plus y is two to fifty, x and y are whole numbers, n isa whole number from one to three, and Z is a surface inactive anion, anda sodium lignosulfonate having about 0.5 to 4.0 moles of sulfonation permole of lignin, into an aqueous acid coagulating bath containing 2.5% to7% sulfuric acid, 3 to 15% zinc sulfate, and 5 to 20% sodium sulfate, toform filamentary yarn therefrom, withdrawing said yarn from said bath,passing the same through a second hot bath while stretching, completingthe regeneration of said yarn under tension, and collecting the same.

8. A process according to claim 7 wherein said quaternary derivative ofan ethoxylated amine has the following formula:

R-N Cl Elod et al.: Reyon Zellwolle und Andere Chemiefasern, volumeJahrg. 1955, No. 33, page 322.

7. A PROCESS OF PRODUCING VISCOSE YARN WHICH COMPRISES SPINNING AVISCOSE SOLUTION, HAVING INCORPORATED THEREIN ABOUT 0.5 TO 4.0% CIV OF ACOMPOUND OF THE GENERAL FORMULA: